Amid the talk of a possible resignation from President Donald Trump in hopes of being pardoned by President Pence is the realization that Pence most likely will not be able to pardon Trump. Here's how it goes: Trump now has less than 60 days left in his term. At this point, even if Trump were to resign today, Pence could assume the responsibilities of the Presidency without taking the oath of office, under the 25th Amendment, just as if the President were temporarily disabled and in the hospital.
As Acting President, not having taken the Oath of Office, Pence really would not be President. He would be the custodian of the duties of the President, but he would not actually be President. In that capacity, so far as I can determine as a political science scholar, Pence would not have the power of the Presidential pardon available to him.
When Reagan turned power over to Bush
When Ronald Reagan was shot in 1981, he turned over the power of the Presidency to George H.W. Bush, his Vice-President, while he underwent surgery. During the surgery, Bush was Acting President but he did not have Presidential pardon powers nor did he take the Oath of Office as President.
At this point, there are so few days left in Trump's term that Pence most likely would fill in as Acting President without even taking the Oath of Office. And just like Bush in 1981, Pence will not have the pardon powers available to him.
A failing self pardon
It is likely, therefore, that Trump will be advised by his legal team to utilize the one remaining option available to him: pardoning himself. It is unknown at this point if a self-pardon will be successful for Trump. Sources believe the Supreme Court would overturn a self-pardon on the grounds that nobody can fairly judge himself or herself.
State prosecution
Even if Trump is successful at pardoning himself of the federal tax charges against him, he will not be able to relinquish himself of the state charges against him in New York State. Trump will face prosecution after he leaves office. That is for sure, pardon or not.